1. Speed too high.
2. Head lower than rating, pumps too much water.
3. Wrong direction of rotation.
4. Mechanical defects:
a) Shaft bent.
b) Rotating element binds.
c) Stuffing box too tight.
d) Wear rings worn.
e) Bearings worn.
f) Casing packing defective.
g) Pump and drive unit misaligned.
2. Head lower than rating, pumps too much water.
3. Wrong direction of rotation.
4. Mechanical defects:
a) Shaft bent.
b) Rotating element binds.
c) Stuffing box too tight.
d) Wear rings worn.
e) Bearings worn.
f) Casing packing defective.
g) Pump and drive unit misaligned.